Heating tool

ABSTRACT

A method of curing an aircraft component including applying a temperature sensitive adhesive to a surface of a component, the surface having a contour; positioning a heating tool including a manifold with a ventilation path such that the ventilation path is adjacent to the surface by aligning the ventilation path to the contour of the component; and heating the surface of the component with uniform airflow from the ventilation path; wherein the manifold includes a chamber with a diverging portion configured to provide uniform airflow through the ventilation path to provide heating to the surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a divisional of U.S. patent application Ser.No. 15/424,565, filed Feb. 3, 2017, which claims the benefit of thefiling date of U.S. provisional application No. 62/292,729, filed Feb.8, 2016, the disclosures of which are hereby incorporated by reference.

BACKGROUND Field of the Invention

The present disclosure relates to a heating tool and method of heating asurface, and in particular, to a heating tool for heating surfaces andcomponents in a tiltrotor aircraft wing.

Description of Related Art

Modern aircraft are manufactured from a wide variety of materials,including steel, aluminum, and a wide variety of composite materials.Most structural components are made from strong, rigid materials.However, in order to conserve weight, the structural components areoften made from a thin layer of metal or composite that includesreinforcement strips of material reinforced with stringers.

Tiltrotor aircraft have complicated proprotor assemblies located atopposing wing tips that operate between a helicopter mode to take off,hover, fly, and land like a conventional helicopter; and an airplanemode. The proprotor assemblies are oriented vertically for a helicoptermode and horizontally for airplane mode. Because the tiltrotor aircraftmust operate in both helicopter mode and airplane mode, and operatewhile transitioning between the two, the wing structure must support theweight of the proprotor assemblies, withstand the forces generated fromthe proprotor assemblies in a variety of modes, and provide a liftingforce sufficient to lift the weight of the aircraft.

FIG. 1 is a partial view of an exemplary prior art tiltrotor wing 10including a torque box structure 30. The torque box structure 30includes skins 20, forward spar 32, and aft spar 34. The skins 20includes stringers 12 extending generally parallel to the longitudinalaxis of the wing 10. The upper skin 22 requires five stringers 12 andthe lower skin 24 requires four stringers 12. The stringers 12 providestiffness and support to the skin 20 and are each an I-beam shapedstiffener as shown in FIG. 2 connected to the interior surface 20 a ofthe skin 20. The stiffeners 12 are made from a composite material andextend the depth of the skin 20 assembly into the interior of the wing10 thereby reducing the space available for fuel and other internalsystems.

The skin 20 is constructed of many of layers or “plies” of compositematerials including hundreds of reinforcement strips 28 or “postagestamps” made of various types, sizes, orientations, and thicknesses ofmaterials. The reinforcement strips 28 are made of graduated sizes ofpostage stamp stamps that have been compacted together as shown in FIG.2 . The reinforcement strips 28 are located below the stringer 12: (1)to provide support for the skin 20 against catastrophic buckling; (2) tomaintain shape and contour of the skin 20; (3) to provide stiffness atthe stringer load points; and (4) to distribute pressure into the skin.

During manufacture of the skin 20 each of the reinforcement strips 28 iscut, labeled, and positioned in a mold, which is an extremelytime-consuming and laborious process. When the size and shape of areinforcement strip 28 is used repeatedly, a problem results in that thereinforcement strips 28 are pre-cut and stored in a controlledatmosphere environment and must be identified and thawed by a user eachtime a reinforcement strip is needed for a composite.

The stringers 12 are connected to the torque box structure 30 usingrivets or other suitable means. The torque box structure 30 furtherincludes lower supports 36, and upper supports 38. The lower and uppersupports 36, 38 provide horizontal structural strength to the forwardand aft spars 32, 34 and to the respective upper and lower skins 22, 24.The lower and upper supports 36, 38 are stiffening elements to keep therib from buckling and act as a doubler around an access hole through therib. The lower and upper supports 36, 38 are individual manufacturedcomposite parts that are mechanically fastened during the rib install,which increases the part count and time for assembly of the overall wingstructure. As shown in FIG. 1 , the torque box structure 30 includesmultiple internal supports that reduces the space available for fuel andother internal systems.

The assembly of the torque box structure 30 is very complex, often withvery tight tolerances required. The installation of the fasteners to theskins 20 and other structural components is also difficult because thereis limited access to small interior spaces and complicated sealingrequirements. Moreover, a large number of fasteners is required for eachwing 10, which can cause the structures to warp and dimensional growthduring assembly. Once the structural members are assembled, over ahundred foam details are positioned between the structural members inthe fuel bays to provide a smooth, ramped surface for the fuelcomponents housed therein. The assembly of the torque box 30 is timeconsuming and extremely labor intensive at each of the various stages ofmanufacture (manufacture of the composites, sub-assembly, installationstages).

The wing structure in FIGS. 1 and 2 is a cross-sectional view of a priorart tiltrotor swept, dihedral wing that concentrates loads at theoutboard ends and inboard ends adjacent to the fuselage; which requiresstructural reinforcement in those areas to withstand twisting andtorsional forces during the various flight modes. The front sparrequires three spars and the back requires five spars along with tipspars to provide sufficient structural strength for the swept, dihedralwing.

Accordingly, the need has arisen for an improved wing structure,assembled components, and methods for manufacture thereof for use on atiltrotor aircraft that addresses one or more of the foregoing issues.

SUMMARY

In a first aspect, a heating tool includes a heat source having adischarge outlet; and a manifold including an intake conduit configuredto releasably connect to the discharge outlet of the heat source and achamber coupled to the intake conduit having a ventilation path. Thechamber includes a diverging portion configured to provide uniformairflow through the ventilation path to provide heating to a surface.

In an embodiment, the chamber comprises a first portion and a secondportion.

In one embodiment, the first and second portions of the chamber and theintake conduit are configured for assembly and disassembly.

In another embodiment, the diverging portion is a convex portion thatprotrudes away from the ventilation path.

In still another embodiment, the ventilation path is configured topermit heated airflow therethrough and onto the surface.

In certain embodiments, the surface includes a contour and theventilation path generally aligns with the contour.

In an embodiment, the surface is a bondline and the ventilation pathgenerally aligns with the bondline.

In yet another embodiment, the heating tool includes an alignment memberto align the ventilation path with the surface.

In an embodiment, the ventilation path is comprised of a plurality ofapertures.

An embodiment provides that the surface is in a torque box assembly.

In one embodiment, the surface is in a fuel bay of the torque boxassembly.

In a second aspect, there is a method of curing an aircraft componentincluding applying a temperature sensitive adhesive to a surface of acomponent, the surface having a contour; positioning a heating toolincluding a manifold with a ventilation path such that the ventilationpath is adjacent to the surface by aligning the ventilation path to thecontour of the component; and heating the surface of the component withuniform airflow from the ventilation path. The manifold includes achamber with a diverging portion configured to provide uniform airflowthrough the ventilation path to provide heating to the surface.

In an embodiment, the heating step provides localized heating to thesurface.

In one embodiment, the heating step includes heating the surface fromambient temperature to about 350 F.

In certain embodiments, the positioning step includes positioning themanifold such that the ventilation path is located within a heating zoneof the surface.

In still some embodiments, the method includes assembling a firstportion and a second portion of the chamber prior to the positioningstep.

In yet another embodiment, the method includes assembling an intakeconduit to a heat gun and assembling the intake conduit to the manifold.

In an embodiment, the positioning step includes positioning an alignmentmember to align the ventilation path with the surface.

An embodiment provides that the positioning step includes supporting themanifold with an alignment member.

Another embodiment provides that the positioning step includesassembling a first portion and a second portion of the chamber.

Other aspects, features, and advantages will become apparent from thefollowing detailed description when taken in conjunction with theaccompanying drawings, which are a part of this disclosure and whichillustrate, by way of example, principles of the inventions disclosed.

DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the embodiments of thepresent disclosure are set forth in the appended claims. However, theembodiments themselves, as well as a preferred mode of use, and furtherobjectives and advantages thereof, will best be understood by referenceto the following detailed description when read in conjunction with theaccompanying drawings, wherein:

FIG. 1 is a cross-sectional view of a prior art tiltrotor wing;

FIG. 2 is a cross-sectional view of a stringer and skin in the prior arttiltrotor wing shown in FIG. 1 ;

FIG. 3 is a perspective view of a tiltrotor aircraft in helicopter mode,according to one example embodiment;

FIG. 4 is a perspective view of a tiltrotor aircraft in airplane mode,according to one example embodiment;

FIG. 5 is a top level schematic view diagram of a method ofmanufacturing a tiltrotor wing structure, according to an exemplaryembodiment;

FIG. 6 is an exploded schematic view of a composite lay-up used in theconstruction of the composite skin, according to an exemplaryembodiment;

FIG. 7 is a flow diagram of a method of manufacturing a composite,according to an exemplary embodiment;

FIG. 8 is an enlarged, cross-sectional view of a portion of a compositeskin, according to an exemplary embodiment;

FIG. 9 is a flow diagram of a method of manufacturing a composite,according to an exemplary embodiment;

FIG. 10A is a perspective view of an illustrative embodiment of acomposite skin, according to an exemplary embodiment;

FIG. 10B is a top view of a portion of a honeycomb core for a compositeskin, according to an exemplary embodiment;

FIG. 11 is an exploded perspective view of a composite skin assembly,according to an exemplary embodiment;

FIG. 12 is a perspective view of a composite skin assembly, according toan exemplary embodiment;

FIG. 13 is a partial perspective view of the composite skin assembly,according to an exemplary embodiment;

FIG. 14 is a side view of a joint member in a composite skin assembly,according to an exemplary embodiment;

FIG. 15 is a perspective view of a joint member in a composite skinassembly, according to an exemplary embodiment;

FIG. 16 is an exploded perspective view of a rib assembly, according toan exemplary embodiment;

FIG. 17 is a perspective view of a rib assembly, according to anexemplary embodiment;

FIG. 18A is a perspective view of a rib assembly attached to rib posts,according to an exemplary embodiment;

FIG. 18B is a perspective view of an engagement member including anintegral rib post, according to an exemplary embodiment;

FIG. 18C is a perspective view an engagement member connected to a leftspar assembly, a right spar assembly, and a rib assembly, according toan exemplary embodiment;

FIG. 19 is a flow diagram of a method of manufacturing a tiltrotor wingstructure, according to an exemplary embodiment;

FIG. 20A is a schematic side view of a composite lay-up on a mold usedin the construction of cured spar member, according to an exemplaryembodiment;

FIG. 20B is a stylized perspective view of a composite lay-up used inthe construction of a cured spar member, according to an exemplaryembodiment;

FIG. 20C is a side view of a composite used in the manufacture of acomposite spar, according to an exemplary embodiment;

FIG. 20D is a schematic side view of a spar member in a numericallycontrolled machining assembly, according to an exemplary embodiment;

FIG. 21A is an exploded view of a spar assembly, according to anexemplary embodiment;

FIG. 21B is a perspective view of a clevis, according to an exemplaryembodiment;

FIG. 21C is a perspective, schematic view of a spar assembly in afixture, according to an exemplary embodiment;

FIG. 22A is a schematic view diagram of a method for installing a lowercomposite skin assembly to a forward spar assembly and an aft sparassembly, according to an exemplary embodiment;

FIG. 22B is a perspective view of an engagement member, according to anexemplary embodiment;

FIG. 23 is a schematic view diagram of a method of installing aplurality of rib assemblies and upper skin composite to form a torquebox assembly, according to an exemplary embodiment;

FIG. 24A is a schematic view of a heating tool in a bay of a torque boxassembly, according to an exemplary embodiment;

FIG. 24B is a schematic view of a heating tool heating an adhesive tosecure a rib assembly to an upper composite skin assembly, according toan exemplary embodiment;

FIG. 24C is a top perspective view of a heating tool, according to anexemplary embodiment;

FIG. 24D is an exploded perspective view of a heating tool including achamber with a first portion and a second portion, according to anexemplary embodiment;

FIG. 24E is a bottom perspective of a heating tool, according to anexemplary embodiment;

FIG. 24F is a perspective view of a heating tool with an alignmentmember, according to an exemplary embodiment;

FIGS. 24G and 24H are top view of a heating tool with alignment members,according to exemplary embodiments;

FIG. 24I is a flow diagram of a method of curing using a heating tool,according to an exemplary embodiment;

FIG. 25A is a schematic side view of a torque box assembly with aft andforward spars assemblies according to the embodiment shown in FIG. 20C,according to an exemplary embodiment;

FIGS. 25B and 25C are side views of an exemplary embodiment of an aftand a forward spar members, respectively, according to an exemplaryembodiment;

FIG. 25D is a schematic side view of a torque box assembly with the aftand forward spar members shown in FIG. 25B and FIG. 25C, according to anexemplary embodiment;

FIG. 25E is a schematic side view of a torque box assembly with analternate embodiment of the aft and forward spar members, according toan exemplary embodiment; and

FIG. 26 is a schematic view diagram of a method of installing a leadingedge assembly, a cove edge assembly, and fuel access covers to form awing structure; according to an exemplary embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Illustrative embodiments of the apparatus and method are describedbelow. In the interest of clarity, all features of an actualimplementation may not be described in this specification. It will ofcourse be appreciated that in the development of any such actualembodiment, numerous implementation-specific decisions must be made toachieve the developer's specific goals, such as compliance withsystem-related and business-related constraints, which will vary fromone implementation to another. Moreover, it will be appreciated thatsuch a development effort might be complex and time-consuming but wouldnevertheless be a routine undertaking for those of ordinary skill in theart having the benefit of this disclosure.

In the specification, reference may be made to the spatial relationshipsbetween various components and to the spatial orientation of variousaspects of components as the devices are depicted in the attacheddrawings. However, as will be recognized by those skilled in the artafter a complete reading of the present application, the devices,members, apparatuses, etc. described herein may be positioned in anydesired orientation. Thus, the use of terms such as “above,” “below,”“upper,” “lower,” or other like terms to describe a spatial relationshipbetween various components or to describe the spatial orientation ofaspects of such components should be understood to describe a relativerelationship between the components or a spatial orientation of aspectsof such components, respectively, as the device described herein may beoriented in any desired direction.

Referring to FIGS. 3 and 4 , a tiltrotor aircraft 101 is illustrated.Tiltrotor aircraft 101 can include a fuselage 103, a landing gear 105, atail member 107, a wing 109, a propulsion system 111, and a propulsionsystem 113. Each propulsion system 111, 113 includes a fixed engine anda rotatable proprotor 115, 117, respectively. Each rotatable proprotor115, 117 have a plurality of rotor blades 119, 121, respectively,associated therewith. The position of proprotors 115, 117, as well asthe pitch of rotor blades 119, 121, can be selectively controlled inorder to selectively control direction, thrust, and lift of tiltrotoraircraft 101.

FIG. 3 illustrates tiltrotor aircraft 101 in helicopter mode, in whichproprotors 115 and 117 are positioned substantially vertical to providea lifting thrust. FIG. 4 illustrates tiltrotor aircraft 101 in anairplane mode, in which proprotors 115, 117 are positioned substantiallyhorizontal to provide a forward thrust in which a lifting force issupplied by wing 109. It should be appreciated that tiltrotor aircraftcan be operated such that proprotors 115, 117 are selectively positionedbetween airplane mode and helicopter mode, which can be referred to as aconversion mode.

The proprotors 115 and 117 rotate from a conversion axis C located abovean upper wing skin 123. An advantage of locating the conversion axis Cof the proprotors 115 and 117 above the upper wing skin 123 is that thefore/aft location of the proprotors 115 and 117 can be moved to shiftthe center of gravity of the aircraft in the various flight modes asdescribed by U.S. Pat. No. 9,174,731, issued Nov. 3, 2015, which ishereby incorporated by reference in its entirety. As such, locating theconversion axis of the proprotors 115 and 117 above the upper wing skin123 allows the fore/aft location of the proprotors 115 and 117 to beoptimized for the center of lift in a particular flight mode.

The aircraft 101 has a maximum range further than a conventionaltiltrotor aircraft (wing shown in FIGS. 1 and 2 ) achieved at least inpart by the wing structure described herein. The wing structure 109provides structural support for the propulsion systems 111, 113 andfuselage 103 and lifting force sufficient to lift the weight of theaircraft 101. The wing structure 109 is configured to distribute loadsand the shearing motion generated by the propulsion systems 111, 113during the various flight modes. The improved structural support of thewing member 109 also provides fuel bays having no !-beam projections onthe fuel supporting surfaces, which provides more space in the fuel bayfor fuel capacity.

The method for manufacture 130 of a tiltrotor wing structure 109 willfirst be briefly summarized with reference to FIG. 5 , illustrating themajor process steps. After this brief overview, the separate steps,components, sub-assembled parts included in the method for manufacture130 will be explained in detail.

FIG. 5 illustrates a method for manufacture 130 of a tiltrotor wingstructure 109. The method begins with the manufacture of compositematerials for the various assembled components in step 131, shown inFIGS. 6-10B, 19, and 20A-20C, including, but not limited to, an aft sparassembly 141, a forward spar assembly 143, a lower composite skinassembly 151, an upper composite skin assembly 153, and a plurality ofrib assemblies 155. A plurality of cured composite spar members 141R,141L, 143R, 143L are sub-assembled along with engagement members 145,rib posts 146, and other components to form the aft spar assembly 141and forward aft spar assembly 143 in steps 133 and 135. In anembodiment, the rib posts 146 are assembled onto an interior surface ofthe aft and forward spar assemblies 141, 143. Next, the components forthe anchor assemblies 147 and the lower skin assembly 151 are installedonto the aft and forward spar assemblies 141, 143 in step 135. Aplurality of rib assemblies 155 are installed between the aft andforward spar assemblies 141, 143 and the upper skin composite assembly153 installed thereon in steps 137, 139 to form a torque box assembly157. A leading edge assembly 159, a cove edge assembly 161, and aplurality of fuel covers 163 are installed on the torque box assembly157 in step 140 to form the wing structure 165 for a tiltrotor aircraft101.

Further, the methods of manufacture, composites, sub-assemblies, andinstalled components described herein are illustrated in the context oftiltrotor aircraft 101; however, the methods of manufacture, composites,sub-assemblies, and installed components can be implemented on otheraircraft and aircraft components; for example, and not limitation,fuselage, tail member, aircraft walls, and aircraft floors for unmannedand manned aircraft.

The manufacture of composite materials for various assembled componentsin step 131 can include a method of making a pre-cured laminate in amold 170 shown in FIGS. 6 and 7 . An exemplary mold 190 is illustratedin FIG. 6 includes a first member 192. The first member 192 includes acavity 196 formed therein having a periphery 198 defined by a forwardedge 198 a, aft edge 198 b, and outboard ends 198 c, 198 d. It should beappreciated that mold 190 may be divided up into any number of separatemembers and can have second, third, or more members. Cavity 196represents the desired geometry of a laminate; for example, and notlimitation, the laminate can be a lower skin, an upper skin, a spar, afloor, a rib web, and a fuselage for an aircraft.

A step 172 of method 170 includes selecting a first plurality of resinimpregnated plies that continuously extend beyond the periphery 198 ofthe mold, the first plurality of resin impregnated plies 173 includes atleast 50 percent (e.g., 51, 52, 53, 54, 55, 56, 57, 58, or 59 percentmore) of the total number of plies. In an embodiment, the firstplurality of resin impregnated plies 173 is from about 50 percent toabout 90 percent of the total number of plies. In another embodiment,the first plurality of resin impregnated plies 173 is from about 52percent to about 80 percent of the total number of plies. In anotherembodiment, the first plurality of woven 173 resin impregnated plies isfrom about 54 percent to about 75 percent of the total number of plies.The first plurality of resin impregnated plies 173 is configured toprovide a plurality of reinforcing ply layers that extends beyond theperimeter 198 of the cavity 196 to assist in reinforcing the overallstiffness and strength of the laminate. In an embodiment, the operatorunrolls a full width ply using a straight edge on one side of the mold190 to insure proper orientation of the ply is made.

A step 174 of method 170 includes selecting a second plurality of resinimpregnated plies 175 that do not extend beyond the forward edge 198 aand continuously extend beyond the aft edge 198 b. In an embodiment, thesecond plurality of resin impregnated plies 175 is from about 15 percentto about 25 percent of the total number of plies. The second pluralityof resin impregnated plies 175 can provide stiffness and strengthgenerally along the aft edge of a pre-cured laminate.

A step 176 of method 170 includes selecting a third plurality of resinimpregnated plies 177 that do not extend beyond the aft edge 198 b andcontinuously extend beyond the forward edge 198 a. In an embodiment, thethird plurality of resin impregnated plies 177 is from about 15 percentto about 25 percent of the total number of plies. The third plurality ofresin impregnated plies 177 can provide stiffness and strength along theforward edge of a pre-cured laminate.

In another embodiment, a portion of the third plurality of resinimpregnated plies 177 do not extend beyond the outboards edges 198 c,198 d of the cavity 196 in the first mold member 192. The portion of thethird plurality of resin impregnated plies 177 that do not extend beyondthe outboard edges 198 c, 198 d can be from about 3 percent to about 7percent of the total number of plies. The portion of the third pluralityof resin impregnated plies 177 that do not extend beyond the outboardedges 198 c, 198 d can provide stiffness and strength generally alongthe central portion of the forward edge in a pre-cured laminate.

A step 178 of method 170 includes selecting a fourth plurality of resinimpregnated plies 179 that do not extend beyond the outboard ends 198 c,198 d and continuously extend beyond the forward and aft edges 198 a,198 b. In an embodiment, the fourth plurality of resin impregnated plies179 is from about 5 percent to about 50 percent of the total number ofplies. The fourth plurality of resin impregnated plies 179 can providestiffness and strength generally along the central portion of apre-cured laminate.

In an embodiment for a laminate for a wing skin, the fourth plurality ofresin impregnated plies 179 includes from about 5 percent to about 15percent of the total number of plies. In another embodiment for alaminate for a wing skin, the fourth plurality of resin impregnatedplies 179 is from about 45 percent to about 50 percent of the totalnumber of plies.

The plies can be at least one of a fabric and a tape. In one embodiment,the plies are pre-impregnated with an un-cured resin. The resin can beapplied to a conventional paper liner and transferred to the ply orapplied directly to the ply and then heated to melt and infuse the resintherein. Prior to layup in a mold, a portion of the conventional linercan be removed and a detection liner can be applied to one or more ofthe sides of a resin impregnated ply, which can assist manufacturingtechniques. The plies can be made from a fiber that is composed ofcontinuous filaments or fibers including one or more of glass, carbon,graphite, basalt, an aromatic polyamide (i.e. “aramid”) material, avariant of an aromatic polyamide material (e.g., a polyparaphenyleneterephthalamide material, such as Kevlar® by E.I. du Pont de Nemours andCompany of Richmond, Va.), or the like. However, the continuousfilaments or fibers described herein can include any suitable materialor combination of materials. The resin can be a polymeric matrix or anysuitable resin system, such as a thermoplastic or thermosetting resin.Other exemplary resins can include epoxy, polyimide, polyamide,bismaleimide, polyester, vinyl ester, phenolic, polyetheretherketone(PEEK), polyetherketone (PEK), polyphenylene sulfide (PPS), and thelike. In an embodiment, the fabric is a woven fabric. In anotherembodiment, the tape is a unidirectional tape.

In an embodiment, the plies can be an intermediate modulus epoxy resinimpregnated carbon fiber fabric. The intermediate modulus epoxyimpregnated carbon fiber fabric can be stiffer than conventionalcomposite fabrics which allows for fewer plies, which reduces the weightand manufacturing cost, while the epoxy resin system can providetolerance to damage.

It should be appreciated that even though the method 170 is describedwith resin impregnated plies, other composite manufacturing process maybe used. For example, a resin transfer molding process, which involvesfabric layers, without being impregnated without resin, being placed ina selected pattern within a mold. Further, resin is transferred into themold such that the fibers and resin are combined, and then cured. Theresin transfer molding process is an exemplary variation of a compositemanufacturing process that is compatible with the embodiments disclosedherein. For example, in an embodiment of step 172 the first plurality ofplies 173 can be plies that undergo a resin transfer molding process toinject resin into the fabric or tape laid in the cavity 196. The firstplurality of plies 173 are at least one of fabric and tape plies thatcontinuously extend beyond the periphery 198 of the mold 190 and areinjected with a resin while positioned in the mold 190.

Each fabric ply is considered a ply or layer in the total number ofplies for a laminate. In an embodiment, the total number of plies isfrom about 8 plies to about 100 plies for a composite article; forexample, and not limitation, an exterior layer in an aircraft skin. Inyet another embodiment, the total number of plies is from about 20 pliesto about 60 plies for a composite article; for example, and notlimitation, a layer in an aircraft skin and a spar. In still anotherembodiment, the total number of plies is from about 40 plies to about 60plies. In another embodiment, the total number of plies is from about 20plies to about 30 plies. In an embodiment, the total number of plies isfrom about 10 plies to about 20 plies. In an illustrative embodimentshown in FIG. 6 , the total number of plies is the total plies of firstplurality of plies 173, the second plurality of plies 175, the thirdplurality of plies 177, and the fourth plurality of plies 179.

A step 180 of method 170 includes laying down the plies in the mold 190.The step 180 can include smoothing the plies to remove any pockets ofair. In an embodiment, each fabric ply is positioned against a fence ortool detail located beyond the periphery 198 to ensure that the ply isin proper alignment in the mold 190.

The plies can be oriented at various patterns of orientation as neededfor the particular laminate being formed. The plies of first pluralityof resin impregnated plies 173 are laid down one at time in the cavity196 of the first mold member 192 such that each ply continuously extendsin the cavity 196 and beyond the perimeter 198 of mold 190.

The plies of the second plurality of resin impregnated plies 175 arelaid down one at time in the cavity 196 of the first mold member 192 sothat each ply extends beyond the aft edge 198 b and does not extendbeyond the forward edge 198 a, as shown in FIG. 6 . Each forward edge175 a of the second plurality of resin impregnated plies 175 ispositioned inside of the forward edge 198 a of the cavity 196 in thefirst mold member 192 while the aft edge 175 b of the second pluralityof the plies extends beyond the aft edge 198 b of the cavity 196.

The plies of the third plurality of resin impregnated plies 177 are laiddown one at time in the cavity 196 of the first mold 192 so that each ofthe plies extends beyond the forward edge 198 a and does not extendbeyond the aft edge 198 b. Each aft edge 177 b of the third plurality ofresin impregnated plies 177 is positioned inside of the aft edge 198 bof the cavity 196 in the first mold member 192 while the forward edge177 a of the second plurality of the plies extends beyond the forwardedge 198 a of the cavity 196.

The plies of the fourth plurality of resin impregnated plies 179 arelaid down one at time in an area over the cavity 196 of the first mold192 so that each of the plies does not extend beyond the outboard ends198 c, 198 d and extend beyond the forward and aft edges 198 a, 198 b.Each of the outboard ends 179 c, 179 d of the fourth plurality of resinimpregnated plies is positioned inside of the outboard ends 198 c, 198 dof the cavity 196 in the first mold member 192 while the forward and aftedges 179 a, 179 b of the plies extend beyond the forward and aft edges198 a, 198 b, respectively.

A step 182 of method 170 includes compacting the plies to provideadequate attachment between the plies. The compacting step can beachieved by applying a vacuum to the plies in the mold or by pressing asecond mold member on the plies disposed in the cavity 196. After theplies are compacted, the plies are cured in step 184 to form a pre-curedlaminate that extends beyond the periphery 198 of the mold 190. Thecuring step can include heating the plies for two hours at 350 degreesFahrenheit at 90 psi.

A step 186 of method 170 can include trimming the pre-cured laminate sothat the pre-cured laminate is reduced to at least the periphery of themold.

An embodiment provides a pre-cured laminate, which can be a first skin201 or a second skin 211 shown in FIG. 8 , having a total number ofplies that includes the first plurality of resin impregnated plies 173that continuously extend beyond the periphery 198 of the mold 190 andcomprise at least 50 percent of the total number of plies. In anembodiment, the first plurality of resin impregnated plies 173 comprisesfrom about 50 percent to about 90 percent of the total number of plies.

In still another embodiment, the pre-cured laminate can include thefirst plurality of resin impregnated plies 173 from about 10 percent toabout 50 percent of the total number of plies. In yet anotherembodiment, the pre-cured laminate can include the first plurality ofresin impregnated plies 173 from about 15 percent to about 40 percent ofthe total number of plies. In yet another embodiment, the pre-curedlaminate can include the first plurality of resin impregnated plies 173from about 30 percent to about 45 percent of the total number of plies.In one embodiment, the pre-cured laminate can include the firstplurality of resin impregnated plies 173 from about 5 percent to about15 percent of the total number of plies.

In an embodiment, the pre-cured laminate further includes the secondplurality of resin impregnated plies 175 that do not extend beyond theforward edge 198 a and continuously extend beyond the aft edge 198 b.The second plurality of resin impregnated plies 175 can be from about 15percent to about 25 percent of the total number of plies.

In one embodiment, the pre-cured laminate includes the third pluralityof resin impregnated plies 177 that do not extend beyond the aft edge198 b and continuously extend beyond the forward edge 198 a. The thirdplurality of resin impregnated plies 177 can be from about 15 percent toabout 25 percent of the total number of plies.

In yet another embodiment, there is a portion of the third plurality ofplies 177 that do not extend beyond the outboard end and comprises fromabout 3 percent to about 7 percent of the total number of plies.

In another embodiment, the pre-cured laminate includes the fourthplurality of resin impregnated plies 179 that do not extend beyond theoutboard ends 198 c, 198 d and continuously extend beyond the forwardand aft edges 198 a, 198 b. The fourth plurality of resin impregnatedplies 179 can be from about 5 percent to about 50 percent of the totalnumber of plies.

In an embodiment, the total number of plies in the pre-cured laminate isfrom about 8 plies to about 100 plies for a composite article. In yetanother embodiment, the total number of plies in the pre-cured laminateis from about 20 plies to about 60 plies. In still another embodiment,the total number of plies in the pre-cured laminate is from about 40plies to about 60 plies. In another embodiment, the total number ofplies in the pre-cured laminate is from about 20 plies to about 30plies. In an embodiment, the total number of plies in the pre-curedlaminate is from about 10 plies to about 20 plies. In an illustrativeembodiment shown in FIG. 6 , the total number of plies in the pre-curedlaminate is the total plies of first plurality of plies 173, the secondplurality of plies 175, the third plurality of plies 177, and the fourthplurality of plies 179.

The method 170 and resulting pre-cured laminate can advantageouslyprovide at least one of the following benefits: plies that cover alarger acreage of a near constant constant-section part, as opposed toplacing a constantly varying amount of material and sizes of materialdown around highly tailored features as shown in the prior art FIG. 2 ;automatic tape lay and fiber placement machines are not required, whichreduces capital costs and material application rates; and a greatlyreduced total ply count and part count as compared to the prior art inFIG. 2 .

The manufacture of composite materials for various assembled componentsin step 131 can include a method of making a composite skin 199 for atorque box 157 of a tiltrotor aircraft 200 shown in FIGS. 8, 9, 10A,10B. The torque box 157, shown in FIG. 5 , has a periphery defined by aforward edge 157 a, an aft edge 157 b, and outboard ends 157 c, 157 d.In an embodiment, the composite skin 199 is used to manufacture acomposite skin assembly 150, which can be an upper composite skinassembly 151 and the lower composite skin assembly 153.

A step 202 in the method 200 includes providing a first skin 201 in amold 220. The first skin 201 having a periphery 201 p defined by aforward edge 201 a, an aft edge 201 b, and outboard ends 201 c, 20 d. Inan embodiment, the periphery 201 p of the first skin 201 can generallyalign with the periphery of the torque box 157. In an embodiment, thefirst skin 201 can be a pre-cured laminate having a total number ofplies that is less than or equal to 70 plies, trimmed to connect with anouter perimeter of a torque box 157, and positioned onto a surface ofthe mold 220, as shown in FIG. 10A. In an embodiment, the first skin 201is a pre-cured laminate having from about 40 plies to about 60 plies.

A step 204 in the method 200 includes providing a plurality of honeycombpanels 203 having an array of large cells 205 onto the first skin 201.In an embodiment, each of the honeycomb panels 203 is a panel of largecell honeycomb. The term “honeycomb” means a material comprising aplurality of interconnected cell walls that define a plurality of cells.While many honeycomb materials define hexagonal cells, the scope of thepresent application encompasses materials that define cells of othershapes, such as square, rectangular, and the like. The term “largecell”, for the purposes of this disclosure, means that each cell 205 hasa width W of at least 1 cm. In another embodiment, the width W of thelarge cells is from about 1 cm to about 3 cm. In yet another embodiment,the width W of the larges cells is from about 1.5 cm to about 2.5 cm. Inan embodiment, the height H of the honeycomb panels 203 is at least 1cm. In another embodiment, the height H of the honeycomb panels 203 isfrom 0.5 cm to 4 cm.

It should be appreciated that honeycomb panels 203 can be of a varietyof materials, including but not limited to, composite materials andmetals. The honeycomb panels 203 may be made from materials oriented inone or more directions and can be woven, unwoven, or braided, forexample. In an embodiment, the honeycomb panels 203 are made of resinimpregnated filaments or fibers. The filaments or fibers can be composedof filaments or fibers including one or more of carbon, graphite, glass,basalt, an aromatic polyamide (i.e. “aramid”) material, a variant of anaromatic polyamide material (e.g., a polyparaphenylene terephthalamidematerial, such as Kevlar® by E.I. du Pont de Nemours and Company ofRichmond, Va.), or the like. However, the continuous filaments or fibersdescribed herein can include any suitable material or combination ofmaterials. The resin can be a polymeric matrix or any suitable resinsystem, such as a thermoplastic or thermosetting resin. Other exemplaryresins can include epoxy, polyimide, polyamide, bismaleimide, polyester,vinyl ester, phenolic, polyetheretherketone (PEEK), polyetherketone(PEK), polyphenylene sulfide (PPS), and the like.

Each of the honeycomb panels 203 can be rectangular or any othersuitable shape for connecting the first skin 201 to the second skin 211.In an embodiment, each of the panels 203 is constructed of similarmaterial, shape, and size panels. In other embodiments, the plurality ofhoneycomb panels 203 includes a variety of honeycomb panels having atleast one different material, shape, or size as compared to the otherpanels.

The plurality of honeycomb panels 203 is assembled along thelongitudinal axis A1 of the first skin 201 in the mold 220 in step 206to form a honeycomb core 207 having an outer perimeter within theperiphery of the first skin 201 p. The plurality of honeycomb panels 203can be selectively positioned on the first skin 201 to providestructural stiffness for the first skin 201 and second skin 211, whichcan prevent the first and second skins 201, 211 from buckling duringoperation.

In an embodiment, the honeycomb core 207 can be constructed from onehoneycomb panel that extends spanwise across the wing 109. In anembodiment with a one-piece honeycomb core 207, the one-piece panel canbe filled with an expanded foam, an adhesive, or other filler materialat various locations requiring stiffening or for securing othercomponents thereto. In an embodiment, the one-piece panel can include atleast one integral filler member that are cells with expanded foam,adhesive, or other filler material at locations where the filler members209 are located as shown in FIG. 11 .

In an embodiment, the method 200 can include a step 208 of positioning aplurality of filler members 209 between the plurality of honeycombpanels 203 in the honeycomb core 207, as shown in FIG. 11 . In anembodiment, each of the filler members 209 is a compression moldedmaterial that is machined to the desired shape. In another embodiment,each of the filler members 209 is a net-molded part not requiringmachining. The compression molded material can be a curable moldablematerial, for example, and not limitation, a thermosetting resins andadvanced composite thermoplastics with unidirectional tapes, wovenfabrics, randomly orientated fiber mat, or chopped strand. Each of thefiller members 209 is butt jointed to the adjacent honeycomb panels 203.In an embodiment shown in FIGS. 10 and 11 , each of the outboard ends207 c, 207 d of the honeycomb core 207 includes a filler member 209thereon that can provide a fluid barrier for the plurality of honeycombpanels 203 in the honeycomb core 207. The plurality of filler members209 are oriented generally perpendicular to the longitudinal axis A1 ofthe first skin. In an embodiment, the filler members 209 can providecompressive strength to the composite skin 199 and provide stiff surfacefor fasteners to attach thereto during later installation steps.

In an embodiment, each of the filler members 209 is adhesively bonded tothe first and second skins 201, 211. In another embodiment, each of thefiller members 209 can be fastened to the first skin 201 usingconventional aerospace fasteners. The term “fasteners” means pins,screws, rivets, or other suitable aerospace fasteners. In an embodiment,the plurality of filler members 209 are a portion of the honeycomb core207.

A second skin 211 is positioned onto the honeycomb core 207 in step 210and has outer perimeter within the periphery of the torque box. In anembodiment, the second skin 211 is a pre-cured laminate having a totalnumber of plies less than the first skin 201. In another embodiment, thesecond skin 211 is a pre-cured laminate having less than 60 plies. Anadhesive can be applied in step 212 to a top surface 207 y of thehoneycomb core 207 and to a bottom surface 207 z of the honeycomb core207 for securing the first and second skins 201, 211 to the honeycombcore 207, as shown in FIG. 8 . In an embodiment, the adhesive isreticulated to provide fillets of adhesive between the first skin 201,the honeycomb core 207, and the second skin 211. In an embodiment, thestep of applying adhesive 212 can include applying adhesive to fillermembers 209, honeycomb core 207, and other components. The forward andaft edges 211 a, 211 b of the second skin 211 are aligned to the forwardand aft edges 207 a, 207 b of the honeycomb core 207. The outboard edges211 c, 211 d of the second skin 211 are aligned to the correspondingoutboard edges 207 c, 207 of the honeycomb core 207.

The outer perimeters 207 p, 211 p of the honeycomb core 207 and thesecond skin 211 on their forward edges 207 a, 211 a and aft edges 207 b,211 b are from about 1 cm to about 16 cm from the forward edge 201 a andthe aft edge 201 b of the first skin 201. The outer perimeters 207 p,211 p of the honeycomb core 207 and the second skin 211 on theiroutboard edges 207 c, 207 d, 211 c, 211 d are from about 7 cm to about91 cm from the outboard edges 201 c, 201 d of the first skin 201. Inanother embodiment, the outer perimeters 207 p, 211 p of the honeycombcore 207 and the second skin 211 on their outboard edges 207 c, 207 d,211 c, 211 d are from about 30 cm to about 80 cm from the outboard edges201 c, 201 d of the first skin 201. In other embodiments, the outerperimeters 207 p, 211 p of the honeycomb core 207 and the second skin211 on their outboard edges 207 c, 207 d, 211 c, 211 d form a length CLfrom about 5% to about 90% of the total spanwise length SL of the firstskin 201. In an embodiment, the outer perimeters 207 p, 211 p of thehoneycomb core 207 and the second skin 211 on their outboard edges 207c, 207 d, 211 c, 211 d form a length CL from about 50% to about 80% ofthe total spanwise length SL of the first skin 201.

As shown in FIGS. 10A, 14, and 15 , the forward edges 207 a, 211 a andaft edges 207 b, 2011 b of the honeycomb core 207 and the second skin211 are about 90 degrees relative to the top surface of the first skin201.

If the first skin 201, honeycomb core 207 and the second skin 211 arebeing assembled as a composite skin 199 for a lower skin assembly 151,then the first skin 201, honeycomb core 207, and second skin 211 can betrimmed in step 214 of the method 200. The trimming step 214 can includetrimming a plurality of corresponding openings 213 in the first skin 213a, the honeycomb core 213 b, and the second skin 213 b. In anembodiment, the plurality of openings 213 are of a size sufficient toreceive fuel components and systems. In an embodiment, the openings 213b, 213 c in the honeycomb core 207 and the second skin 211 are larger insize but correspond to the openings 213 a in the first skin 201. Thetrimming in step 214 can be performed by any variety of process, such ascutting, sanding, machining, to name a few examples. FIGS. 11, 12, and13 illustrate the plurality of openings 213 a, 213 b, 213 c trimmed inthe first skin 201, honeycomb core 207, and the second skin 211.

If the first skin 201, honeycomb core 207 and the second skin 211 arebeing assembled as a composite skin 199 for an upper skin assembly 153,the first skin 201, honeycomb core 207, and second skin 211 may betrimmed in step 214 of the method 200; however, the trimming step forthe upper skin assembly 153 can be limited to the perimeter 201 p, 207p, and 211 p of the first skin 201 p, honeycomb core 207, and the secondskin 211.

Once the first skin 201, honeycomb core 207, and the second skin areassembled into a composite skin 199, an embodiment includes positioninga plurality of joint members 215 thereon in step 216 of method 200 asshown in FIGS. 11, 12, 13, and 14 to form a joint system for a compositeskin. Each of the plurality of joint members 215 includes a first flange215 c, a second flange 215 a, and a support member 215 b disposedbetween the first flange 215 c and the second flange 215 a. In anembodiment, the support member 215 b includes a first side 215 f and asecond side 215 s, the first flange 215 a is a lower flange that extendslaterally from the first side 215 f of the support member 215 b and thesecond flange 215 c is an upper flange extends laterally from the secondside 215 s, to form generally a “Z” shape. FIGS. 14 and 15 showexemplary joint members; however, it will be appreciated that thecontemplated embodiments can be configured such that the first flange215 a can be an upper flange and the second flange 215 c can be a lowerflange for joining certain structures.

The exemplary embodiments of the joint member 215 provides that theupper flange 215 c includes an attachment surface 215 n that overlaps aportion of the second skin 211 and attaches thereto. The lower flange215 a includes an attachment surface 215 m that overlaps a portion ofthe first skin 201 and attaches thereto. The upper and lower flanges 215c, 215 a can be fixedly attached to the first and second skin 201, 211,respectively, with at least one of an adhesive and a conventionalfastener (screw, bolt, rivet, etc.).

The plurality of joint members 215 are configured to provide a load pathfrom the first skin 201 to the second skin 211; secure the first skin201 to the second skin 211, which can limit peeling of the honeycombcore 207 away from the first skin 201; and provide a fluid barrier tolimit fluid intrusion, such as fuel, water, and hydraulic fluid, intothe honeycomb core 207.

The joint members 215 can be made from a wide variety of materials,including but not limited to, composite materials and metals. In anembodiment, the joint members 215 are made from a pre-cured laminate asdescribed herein that is trimmed to include the upper flange 215 c,support member 215 b, and the lower flange 215 a as described herein.The joint members 215 can be made from materials oriented in one or moredirections and can be woven, unwoven, or braided, for example. In anembodiment, the joint members 215 are made from a composite materialreinforced with high strength fibers and fabrics configured to transfera load path from the upper flange 215 c to the lower flange 215 a;examples of high strength fibers and fabrics, for example, and notlimitation, include fabric is composed of continuous filaments or fibersincluding one or more of carbon, graphite, glass, an aromatic polyamide(i.e. “aramid”) material, a variant of an aromatic polyamide material(e.g., a polyparaphenylene terephthalamide material, such as Kevlar® byE.I. du Pont de Nemours and Company of Richmond, Va.), or the like. Inanother embodiment, the joint members 215 are made, for example, of ametal such as titanium or a high hardness steel. In an embodiment, eachof the joint members 215 in a plurality of joint members 215 are madefrom similar materials. In other embodiments, the plurality of the jointmembers 215 are made from dissimilar materials, e.g., a portion of thejoint members are made from metallic materials and a portion are madefrom composite materials.

Each of the joint members 215 can be straight, round, or any othersuitable shape for connecting the first skin 201 to the second skin 211.In an embodiment, each of the joint members 215 is constructed ofsimilar material, shape, and size panels. In other embodiments, theplurality of joint members 215 includes a variety of joint membershaving at least one different material, shape, or size as compared tothe other members.

An exemplary embodiment shown in FIGS. 12, 13, and 14 provides aplurality of generally straight joint members 215 are positioned at theforward edges 207 a, 211 a and aft edges 207 b, 211 b of the honeycombcore 207 and the second skin 211. In an embodiment, the joint system caninclude at least at the second skin 211 having an edge of about 90degrees relative to the top surface 201 t of the first skin 201, e.g.,the forward edge 211 a or the aft edge 211 b. In the example embodiment,both the second skin 211 and the honeycomb core 207 have an edge ofabout 90 degrees relative to the top surface 201 t of the first skin201. In another exemplary embodiment, a plurality of generally ovaljoint members 217 can be installed in the plurality of openings 213 andincludes a lower flange 217 a that extends laterally from a greaterdistance first surface 217 f of the support member 217 b as compared tothe joint member 215 along the edges. The size, length, and shape of thejoint members 215, 217 can be tailored to achieve at least one of thefollowing functional properties: provide a fluid barrier to the materialadjacent to the support member 215 s and provide a load path from onecomposite to another composite. In an embodiment, the joint member 217can be a one-piece machined aluminum component that is riveted and roomtemperature bonded to the first and second skins 201, 211, as shown inFIG. 14

The plurality of joint members 215, 217 can be fixedly attached to thefirst and second skin 201, 211, respectively, with at least one of anadhesive and a conventional fastener (screw, bolt, rivet, etc.).

The curing step 218 of method 200 includes curing the composite skin 199by heating the composite skin for about 2 hours at 250 degreesFahrenheit above ambient pressure. If the plurality of joint members215, 217 are composite materials and are included on the composite skin199, the joint members 215, 217 can be cured together with the compositeskin 199, which can co-bond the composite joint members 215, 217 to thefirst and second skins 201, 211, respectively. Prior to the curing step218, adhesive can be applied to at least one of: the first skin 201; thehoneycomb core 207; the filler members 209; the joint members 215, 217;and the second skin 211.

Once the composite skin 199 is cured, it can be used to manufacture thecomposite skin assembly 150. The composite skin 199 can undergo anassembly step that includes accurately drilling of holes to form thecomposite skin assembly 150 that can be at least one of the uppercomposite skin assembly 151 and the lower composite skin assembly 153,which is then ready for installation in step 135 of the method 130 formanufacturing a tiltrotor wing structure 109. The assembly step canfurther include: procuring and attaching details; trimming of holes soas to align with installation fixtures correctly; and preparing thecomposite skin for bonding to form a torque box assembly 157, includingapplying adhesive and or positioning of pins or pegs.

The method of manufacture for a composite skin assembly in FIG. 9 andthe resulting composite skin can advantageously provide at least one ofthe following: a narrow profile honeycomb core stiffened wing skin,which does not include any or require any conventional stringers asshown in FIGS. 1 and 2 ; the straight forward and aft edges of thecomposite skin facilitates assembly and improves strength of the torquebox assembly, as compared to tapered or angled wings, the composite skinprovides sufficient stiffness and torsional support during the shearingmotion produced by the twisting proprotors 115 and 117; low costcomposite tooling as compared to the tooling required for the pieces andply buildups used in the conventional tiltrotor wing shown in FIGS. 1and 2 ; a combination of the methods described herein can reduce overalllabor costs by more than 50% as compared to the current labor costs forthe conventional tiltrotor wing shown in FIGS. 1 and 2 ; the compositeskin is weight efficient and permits a monocoque torque box assembly157; the composite skin includes at least one of a straight forward edgeand a straight aft edge, which facilitates assembly and improvesstrength of the resulting spar assembly; the total ply count and partcount of the composite skins has been reduced by about 75% as comparedto the tiltrotor wing shown in FIGS. 1 and 2 ; the elimination of“postage stamp” ply buildups as shown in FIGS. 1 and 2 reduces the needfor raw material kitting and allows for point-of-use manufacturing forthe composite skins; reduces the number of quality defects as comparedto the quality defects in the conventional tiltrotor wing in FIGS. 1 and2 ; simple de-tooling; the composite skin assembly facilitates repair;and the numerous horizontal and vertical stiffeners needed forconventional wing structure shown in FIGS. 1 and 2 are no longer neededfor buckling resistance and to transfer the load and resist out of planebending forces.

In an embodiment, the composite skin 199 used in a torque box assembly157 as described herein can provide improved fuel bay clearance ascompared to the prior art structure in FIGS. 1 and 2 because thecomposite skin has a thin profile and does not require stringers andother structural members that extend generally into and through theinterior of the fuel bays therein. In addition, the composite skin 199provides a generally flat bottom and flat top with the prefabricatedthat uses only minimal foam fillets in each corner of a fuel bay, whichgreatly reduces the part count and complexity of manufacturing ascompared to the prior art structure in FIGS. 1 and 2 . The compositeskin 199 can be adapted to provide selected stiffness for tiltrotor wingthat combats the dynamic loads and harmonics generated by the propulsionsystems 111, 113 in operation.

The method for manufacture 130 of a tiltrotor wing structure 109includes providing a plurality of rib assemblies 155. In an embodiment,each of the plurality of rib assemblies 155 is a pre-assembled ribassembly ready for installation to form a torque box assembly 157. Eachof the rib assemblies 155 includes a rib web 230 including a firstlaminate 232, a second laminate 234, and a honeycomb panel 236 having anarray of large cells and a plurality of skin flanges 240.

In an embodiment, the first laminate 232 and the second laminate 234 areeach a pre-cured laminate produced by the method 170 in a flat mold.After the pre-curing step 184, the first and second laminates aretrimmed as two pieces to form the first and second laminates 232, 234.In an embodiment, the first and second laminates 232, 234 are eachcomprised of a total number of plies from about 4 plies to about 12plies.

The honeycomb panel 236 is disposed between the first laminate 232 andthe second laminate 234 during sub-assembly of the rib assembly 155. Inan embodiment, the honeycomb panel 236 is a panel of large cellhoneycomb as shown in FIG. 10B. The large cell means that that each cell205 has a width W of at least 1 cm. In another embodiment, the width Wof the large cells is from about 1 cm to about 3 cm. In yet anotherembodiment, the width W of the larges cells is from about 1.5 cm toabout 2.5 cm. In an embodiment, the height H of the honeycomb panel 236is at least 1 cm. In another embodiment, the height H of the honeycombpanel 236 is from 0.6 cm to 12.7 cm.

It should be appreciated that honeycomb panel 236 can be of a variety ofmaterials, including but not limited to, composite materials and metals.The honeycomb panel 236 may be made from materials oriented in one ormore directions and can be woven, unwoven, or braided, for example. Inan embodiment, the honeycomb panel 236 is made of resin impregnatedfilaments or fibers. The filaments or fibers can be composed offilaments or fibers including one or more of carbon, graphite, glass, anaromatic polyamide (i.e. “aramid”) material, a variant of an aromaticpolyamide material (e.g., a polyparaphenylene terephthalamide material,such as Kevlar® by E.I. du Pont de Nemours and Company of Richmond,Va.), or the like. However, the continuous filaments or fibers describedherein can include any suitable material or combination of materials.The resin can be a polymeric matrix or any suitable resin system, suchas a thermoplastic or thermosetting resin. Other exemplary resins caninclude epoxy, polyimide, polyamide, bismaleimide, polyester, vinylester, phenolic, polyetheretherketone (PEEK), polyetherketone (PEK),polyphenylene sulfide (PPS), and the like.

In an embodiment, each of the panels 236 in the rib web 230 in theplurality of rib assemblies 155 is constructed of similar material,shape, and size panels. In other embodiments, the panels 236 in the ribwebs 230 in the plurality of rib assemblies 155 includes a variety ofhoneycomb panels 236 having at least one different material, size, orshape as compared to the other panels in the plurality of rib assemblies155.

The first and second laminates 232, 234 are adhered to the honeycombpanel 236 on interior surfaces thereof by an adhesive that can bebonding at ambient temperature or with a temperature sensitive adhesiveusing a heating tool to form the rib web 230. The rib web 230 hasgenerally smooth exterior surfaces as formed by the first and secondlaminates 232, 234. The rib web 230 has a thin profile or width, whichcan provide the necessary structural support for the wing structure 109without requiring protruding I-beam reinforcement members therethroughas is required in the prior art shown in FIGS. 1 and 2 .

The rib web 230 is then trimmed to the desired shape having a forwardedge 230 a, an aft edge 230 b, a top 230 t, and a bottom 230 o. The ribweb 230 further includes at least two apertures 230 r configured toreceive and support the fuel systems and lines running therethrough. Inone embodiment, the rib web 230 has a width sufficient to prevent kinksin the fuel systems and lines in the apertures 230 r. The rib web 230includes a top 232 t, 236 t, 234 t and a bottom 232 o, 236 o, 234 o thatare fixedly connected to the plurality of skin flanges 240.

A plurality of skin flanges 240 are fixedly attached to the ribassemblies 155 and during installation are secured to the adjacent lowercomposite skin assembly 151 and the upper composite skin assembly 153.In an embodiment, each rib assembly 155 includes a first skin flange242, a second skin flange 244, a third skin flange 246, and a fourthskin flange 248. The first, second, third, and fourth skin flanges 242,244, 246, 248 are substantially similar; therefore, for sake ofefficiency the plurality of skin flanges 240 will be disclosed only withregards to the first skin flange 242. However, one of ordinary skill inthe art would fully appreciate an understanding of the second, third,and fourth skin flanges 244, 246, 248 based upon the disclosure of thefirst skin flanges 242.

The first skin flange 242 includes a base member 242 s having a firstportion 242 f and a second portion 242 d and a vertical member 2421extending from the base member 242 s. In an embodiment, the width of thefirst portion 242 f is more than the width of the second portion 242 d.The second portion 242 d and vertical member 2421 are configured tosecurely attach to the top edge of the rib web 230. In one embodiment,the width of the second portion 242 d of the base member 242 scorresponds to greater than half of the thickness of the rib web 230. Inan embodiment, the second portion 242 d is overlapped by a secondportion 246 d of the base member 246 s of the third skin flange 246, asshown in FIG. 24B. The base member 242 s is ultimately adhered to arespective composite skin assembly 151, 153 during installation to forma torque box structure 157. The base member 242 s is opposite to thesurface having the vertical member 2421.

The vertical member 2421 supports the outer, top surface of the rib web230. In an embodiment, the vertical member 2421 includes a roundedportion 242 u having an opening 242 o that corresponds to the aperture230 r in the rib web 230 as formed by the openings 232 r, 234 r, 236 r.

In an embodiment, the first skin flange 242 is constructed from acomposite material molded to the shape 242. In an embodiment, the firstskin flange 242 is a pre-cured laminate produced by the method 170 in asuitable mold.

The second 242 d portion of the base member 242 s and the verticalmember 2421 of the skin flange 242 are attached to the top and bottom ofthe rib web 230 by bonding at ambient temperature or with a temperaturesensitive adhesive using a heating tool. In an embodiment, the skinflange 242 is structurally bonded to the rib web 230 during a compositecuring process. In a further embodiment, the skin flange 242 is fastenedto the rib web 230 using fasteners.

The rib assembly 230 includes a forward edge 230 a and an aft edge 230b, each of which can be attached forward and aft joint members 250, 252having a “Z” configuration to secure the rib assembly 230 tocorresponding to rib posts 146 in the aft and forward spar assemblies141, 143. The forward and aft joint members 250, 252 can be a firstjoint member 250 and a second joint member 252.

Each of the first and second joint members 250, 252 includes an upperflange 215 c with an attachment surface 215 n that overlaps and issecured to the outer rib web surface 230 being the second laminate 234in this exemplary embodiment. The first and second joint members 250,252 each includes a lower flange 215 a with an attachment surface thatoverlaps and is fixedly connected with forward rib post 256 and aft ribpost 258, respectively. The upper flange 215 c of the first and secondjoint members 250, 252 can be made of a composite or metallic materialthat is bonded, structurally bonded, fastened to, or otherwise connectedto the rib web 230. The lower flange 215 a of the first and second jointmembers 250, 252 is secured to the respective forward and aft rib posts256, 258 using fasteners.

In an embodiment, during installation, each of the rib assemblies 155 isfastened to the forward spar rib post 256 and the aft spar rib post 258such that the first and second joint members 250, 252 are secured to atleast one side of the rib web 230, which can minimize the number offasteners required for installing the rib assembly 155 to the rib posts256, 258. The first and second joint members 250, 252 each include onehole 254 as shown in FIG. 17 for fastening to the respective forward ribpost 256 and aft rib post 258. A plurality of holes can be back-drilledinto the lower flange 215 a of the first and second joint members 250,252 using the holes in the respective forward and aft rib posts 256, 258as a template and the remainder of the fasteners are secured therein. Inan exemplary embodiment, the first joint member 250 is attached toforward rib post 256 with seven fasteners and the second joint member252 is attached to the aft rib post 258 with nine fasteners.

Ina further embodiment shown in FIGS. 18B-18C, during installation, acenterline rib assembly 156 can be secured to an engagement member 145including joining portion 145 j and a post 145 p extending from thejoining portion 145 j. The engagement member 145 can be generally Tshaped. The engagement member 145 can be made of one-piece such that therib post 145 p is integral with the joining portion 145 j andconstructed of at least one of the following: a pre-cured assembly, acomposite material, and a metallic material.

The joining portion 145 j includes a first attachment surface 145 f anda second attachment surface 145 d for attachment and splicing a firstspar 148 f and second spar 148 d to form a spar member. The first andsecond attachment surfaces 145 f, 145 d are exterior surfaces oppositeto interior side 145 i adjacent to the post 145 p.

The joining portion 145 j includes top and bottom sides 145 t, 145 b. Atleast one of the top and bottom sides 145 t, 145 b can include aninterior surface with a slope 145 s increasing the thickness of the topor bottom side 145 t, 145 b at the post 145 p to provide reinforcementfor the rib post 145 p and splicing two spar assemblies. The interiorsurface with a slope 145 s can include at least one step. In anexemplary embodiment, the interior surface with a slope 145 s is astepped surface on both the top and bottom sides 145 t, 145 b.

The post 145 p can be fixedly connected to the centerline rib assembly156 using the first and second joint members 250, 252 connected to therib web 156 w of the rib assembly 156. In one exemplary embodiment, thefirst and second joint members 250, 252 of the centerline rib assembly156 are each fastened to a corresponding forward and aft post 145 p withseven and nine fasteners respectively.

The engagement member 145 serves as a rib post and to join two sparmember 148 f, 148 d. As shown in FIG. 18C, the first spar member 148 fis fixedly connected to the first attachment surface 145 f and thesecond spar member 148 d is fixedly connected to the second attachmentsurface 145 d. In an embodiment, the first and second attachmentsurfaces 145 f, 145 d are on the exterior surface 145 e of theengagement member.

The plurality of rib assemblies 155 can advantageously provide at leastone of the following: a rib assembly 155 requiring minimal fasteners andcomponents; the skin flanges 240 include a thick base member withoverlapping portions that provides improved stability for the ribassemblies 155, the upper skin 153, and the lower skin 151;substantially reduces the number of fuel bay foam details as compared tothe prior art shown in FIGS. 1 and 2 ; the rib web 230 in the assemblies155 has generally smooth surfaces and an overall narrow profile, whichprovides more space or a wider footprint for each bay, as compared tothe prior art shown in FIGS. 1 and 2 requiring protruding stiffeningelements and I-beams, thereby permitting more fuel storage therein; theplurality of skin flanges 240 for each rib assembly 155 provide asurface against the first and second laminates 232, 234 that will resistpeeling from the honeycomb panel 236; production costs and weight areless than conventional rib assemblies used for prior art FIGS. 1 and 2 ,reduced part count as compared to conventional rib assemblies in theprior art FIGS. 1 and 2 ; the size and shape of the shape of the ribassemblies 155 can be tailored for stiffening of various aerospacestructures; and compared to the prior art wing shown in FIGS. 1 and 2 ,the plurality of rib assemblies have about 80% fewer detail parts and70% fewer fasteners per installed rib assembly.

An embodiment of the method of manufacture 130 is schematicallyillustrated in the steps in FIG. 19 identified as a method formanufacturing a tiltrotor wing structure 300.

Method 300 can include a step 302 of providing a spar mold 402.Referring now also to FIGS. 20A, 20B, and 20C, the spar mold 402includes a plurality of bores 410 extending from an exterior surface 402e of the mold 402 to an interior surface of 402 i the mold 402. In anembodiment, the spar mold 402 is made of one piece. In anotherembodiment, the spar mold 402 includes a first mold 404 and a secondmold 406 as shown in FIG. 20B. The first mold 404 includes a pluralityof bores 410 that correspond in location to a plurality of primarycoordination holes 422 in a spar member 418.

In an embodiment, the spar mold 402 is configured for a cured sparmember 418 that can be a portion of the aft spar assembly 141. Inanother embodiment, the spar mold 402 is configured for a cured sparmember 418 that can be a portion of the forward spar assembly 143. In anembodiment, the spar mold 402 is configured to be used as either a leftor right cured spar member 418. In an exemplary embodiment, shown inFIG. 20B, there are twelve bores 410 that can correspond to a pluralityof primary coordination holes 422 in the spar member 418, half of thetwelve bores 410 can be selectively plugged to determine a right or leftsided spar member 418 when the corresponding holes are drilled therein.

In one embodiment, the general height H1 of the support beam 424 of thecured spar member 418 corresponds to the length L1 in the second mold406 where the bottom fabric ply 405 is bent thereby. An embodimentprovides that the length L1 of a mold for the cured spar member 418configured for the forward spar assembly 143 is less than the length L1of a mold for the cured spar member 418 configured for the aft sparassembly 141. As such, the composite molded cured spar member 418 for aforward spar assembly 143 has a height H1 less than the height H1 of thecomposite molded cure spar member 418 for the forward spar assembly 141as shown in FIG. 25A. In an alternate embodiment, the length L1 of amold for the cured spar member 418 configured for the forward sparassembly 143 is more than the length L1 of a mold for the cured sparmember 418 configured for the aft spar assembly 141. As such, thecomposite molded cured spar member 418 for a forward spar assembly 143has a height H2 more than the height H2 of the composite molded curespar member 418 for the forward spar assembly 143.

The second mold 406 includes an interior surface 406 i that resemblesthe desired outer contour of a spar and having a periphery 406 p definedby a top edge 406 t, a bottom edge 406 b, and outboard ends 406 c, 406d. In an embodiment, the second mold 406 has a periphery 406 p definedby a top edge 406 t, a bottom edge 406 b, and outboard ends 406 c, 406d. In one embodiment, the second mold 406 has a periphery 406 p adjacentto the top edge 406 t, bottom edge 406 b, and outboard ends 406 c, 406d. In an embodiment, the periphery 406 p is below the top edge 406 t andbottom edge 406 b. In another embodiment, the second mold 406 has aperiphery 406 p within the top edge 406 t, bottom edge 406 b, andoutboard ends 406 c, 406 d and generally above the cutting periphery 418x at the top edge 406 t and the bottom edge 406 b. In an embodiment, thesecond mold 406 includes a plurality of recesses 406 r to provideminimal clearance for a tool to drill a plurality of primarycoordination holes 422 in a cured spar member 418.

Method 300 can include a step 304 of selecting a plurality of resinimpregnated plies 412. The step 304 can include placing the selectedplurality of resin impregnated plies 412 onto mold 404 in an invertedposition as shown in FIG. 20A then rotating the mold 404 with the plies412 thereon into the second mold 406. In step 304 the selected pluralityof resin impregnated plies 412 continuously extend beyond the periphery406 p of the second mold 406. Step 306 includes laying the plurality ofresin impregnated plies 412 in the spar mold 406 so that the pluralityof resin impregnated plies 412 extend beyond the periphery 406 p of thespar mold 406 as shown in FIGS. 20B-20C. In an embodiment, the pluralityof resin impregnated plies 412 continuously extend beyond the periphery404 p of the first mold 404 in the spar mold 402. In trimming step 322,the plies 412 can be trimmed at line 412 x, which is at a location 406 xwithin or under the periphery 406 p of the mold 406.

A step 308 of the method 300 includes plugging the plurality of bores410 with a plurality of plugs 414, which can assist step 310 ofcompacting the plurality of plies 412 in a mold 402. As shown in FIG.20B, an embodiment provides that six of the twelve plurality of bores410 are plugged 414. In an embodiment, step 310 includes applying avacuum using a vacuum bag surrounding the plurality of plies 412 in themold 402 to compact the plies 412 therein. In another embodiment, step310 includes compacting by pressing of the first mold 404 downward intothe first mold 406.

Step 312 involves curing the plurality of plies 412 in the first andsecond molds 404, 406 to form a cured spar member 418 that extendsbeyond the periphery 406 p of the first mold 406 in the spar mold 402.After curing step 312, the plurality of plugs 414 can be removed fromthe plurality of bores 410 in the first mold 404 in step 314.

Method 300 includes step 316 that involves accurately drilling aplurality of primary coordination holes 422 in the cured spar member 418in the spar mold 402 using a tool 417 in the plurality of bores 410. Thetool 417 can be a drilling tool or other cutting tool that canaccurately drill through the plurality of bores 410 in the mold 404 toform a plurality of primary coordination holes 422 in the spar member481. The plurality of bores 410 act as guide holes that match thecorresponding plurality of primary coordination holes 422 in the sparmember 418 as shown in FIG. 20C. The drill tool 417 can be positionedabove the bore 410 and inserted through the bore 410, into the curedspar member 418, and into a recess 406 r to form a primary coordinationhole 422 in the spar member 418.

In one embodiment, the primary coordination holes 422 are a plurality ofprimary coordination holes that can include from about four to abouttwenty holes in the cured spar member 418. In an embodiment, shown inFIGS. 20B and 21A-21C, there are six primary coordination holes 422 in acured spar member 418 that are positioned at locations that correspondto six bores 410 along the longitudinal axis of the first mold 404. Theterm “primary coordination holes” means a plurality of holes located ona cured spar member 418 that correspond to coordination locations on theaft spar assembly 141 and the forward spar assembly 143 fitted with ribposts 146 thereon. In an embodiment, the primary coordination holes 422receive fasteners 452 to attach arms 450 from a fixture 449 such thatthe fixture 449 supports the aft spar assembly 141 and the forward sparassembly 143. The primary coordination holes 422 determine the positionand location of the spar in the fixture 449 and are used to determinethe location of the rib posts 146 and the associated rib assemblies 155,which is critical to distribute pressure into the upper and lowercomposite skin assemblies 151, 153 and to provide support sufficient toprevent catastrophic buckling of the upper and lower composite skinassemblies 151, 153. Using the mold 402 to establish the location andaccurately drill the primary coordination holes 422 prior to removal ofthe cured spar member 418 from the mold 402 can advantageously provideaccurate relationships between installed components through installationof the torque box assembly 157 and ultimately the entire wing structure109 and is a critical step to ensure that the assembled components(forward spar assembly 143, aft spar assembly 141, upper composite skin153, lower composite skin 151, plurality of rib assemblies 155) areinstalled correctly, accurately, and quickly. Step 316 canadvantageously reduce defects and rework loops that occur duringconventional spar assembly.

After step 316, the cured spar member 418 is cooled and removed from themold 402 and positioned in a numerically controlled machining assembly419 in step 318. The numerically controlled machining assembly 419locates a cutting periphery 418 x of the cured spar member 418 based onthe location of the primary coordination holes 422 in step 320 andreduces the cured spar member 418 to the cutting periphery 418 x in step322. The trimming step 320 uses the information from the locating step322 to identify the trimming periphery or “pattern” for cured sparmember 418. The inventors have found that by using the plurality ofbores 410 in the mold 402 to locate the primary coordination holes 422and subsequently trimming, the cured spar member 418 manufactured bythis process can advantageously provide improved accuracy andconsistency of shape and structure over conventional methods.

In one embodiment, the trimming step 320 reduces the perimeter of thecured spar member 418 to a support beam 424 with integral spar flanges425 that can function to attach the assembled spar to skins and tosupport and hold components attached to the assembled spar, for example,and not limitation, rib posts. The trimming step 320 can includetrimming cured spar member 418 to achieve selected lengths of an upperspar flange 432 and a lower spar flange 434.

In one embodiment shown in FIG. 20D, the cured spar member 418 includesintegral spar flanges 425 having the upper spar flange 432 and the lowerspar flange 434 for attaching to the upper skin composite assembly 153and the lower composite skin assembly 151, respectively. In anembodiment shown in FIGS. 20D and 25A, both the upper and lower sparflanges 432, 434 extend from an interior surface 424 i of the supportbeam 424. Each of the upper and lower spar flanges 432, 436 form anon-acute angle, which means an angle equal to or greater than 90degrees relative to the interior surface 424 i.

FIGS. 25B, 25C, and 25D show embodiments of the cured spar member 518.Certain features of the cured spar member 518 and associated componentsare as described above and bear similar reference characters to thecured spar member 418 and associated components, but with a leading ‘5’rather than a leading ‘4’. The cured spar member 518 includes integralspar flanges 525 having an upper spar flange 532 and a lower spar flange534 for attaching to the upper skin composite assembly 153 and the lowercomposite skin assembly 551, respectively.

In an embodiment shown in FIG. 25B, the upper spar flange 532 extendsfrom the exterior surface 524 e of the support beam 524 for the forwardspar assembly 543. The upper spar flange 532 forms an acute anglerelative to the exterior surface 524 e of the support beam 524. In anembodiment, the upper spar flange 532 is at an angle from about 50degrees to about 85 degrees relative to the exterior surface 524 e. Inan embodiment, the upper spar flange 532 is at an angle from about 60degrees to about 84 degrees relative to the exterior surface 524 e. Inanother embodiment, the upper spar flange 532 is at angle from about 65degrees to about 80 degrees relative to the exterior surface 524 e. Thelower spar flange 534 extends from the interior surface 524 i of thesupport beam 524. The lower spar flange 534 forms a non-acute anglerelative to the interior surface 524 i. The term “non-acute angle” meansan angle equal to or greater than 90 degrees. In one embodiment shown inFIG. 25B, the lower spar flange 534 is at an angle from about 90 degreesto about 115 degrees relative to the interior surface 524 i of thesupport beam 524. This embodiment provides a “Z” spar configuration suchthat at least one of the spar flanges extends outward or to an exteriorportion of the wing structure, which can facilitate the use of automateddrilling and fastening of the skins and other wing components thereto.Automated drilling and fastening can advantageously provide at least oneof the following: improved hole quality and consistent outcomes ascompared to hand drilling and fastening; facilitates the use of clampingpressure during drill operations to prevent the requirement fordis-assembly ad deburr; permits adaptive drilling techniques in mixedmaterial stack-ups, resulting in faster drilling speed, better holequality, and less rejection or rework; and allows the collection and useof the statistical process control data to drive quality and cost.Automated drilling and fastening can achieve a speed of up to 12fasteners per minute, while hand drilling and fastening results in aspeed of 2 minutes per fastener or more when disassembly and deburr timeis included.

FIG. 25C is an embodiment illustrating the upper spar flange 536extending from the exterior surface 524 e of the support beam 524 forthe aft spar assembly 541. The upper spar flange 536 forms an acuteangle relative to the exterior surface 524 e of the support beam 524. Insome embodiments, the upper spar flange 536 is at an angle from about 50degrees to about 85 degrees relative to the exterior surface 524 e ofthe support beam 524. In an embodiment, the upper spar flange 536 is atan angle from about 60 degrees to about 84 degrees relative to theexterior surface 524 e. In another embodiment, the upper spar flange 536is at angle from about 65 degrees to about 80 degrees relative to theexterior surface 524 e. The lower spar flange 538 extends from theinterior surface 524 i of the support beam 524. The lower spar flange538 forms a non-acute angle or an angle greater than 90 degrees relativeto the interior surface 524 i. In one embodiment shown in FIG. 25B, thelower spar flange 534 is at an angle from about 50 to about 85 relativeto the interior surface 524 i of the support beam 524. This embodimentprovides another example of a “Z” spar configuration for an aft sparassembly 541 that includes at least one of the spar flanges extendsoutward or to an exterior portion of the wing structure, which canfacilitate the use of automated drilling and fastening of the skins andother wing components thereto. FIG. 25D includes the “Z” sparconfigurations for the forward spar assembly 543 and the aft sparassembly 541 in a torque box assembly 557. In other embodiments, thetorque box assembly 557 can include a variety of spar configurations andincludes at least one “Z” spar configuration in at least one of theforward spar assembly 543 and aft spar assembly 541.

FIG. 25E shows embodiments of the cured spar member 618 and associatedcomponents. Certain features of the cured spar member 618 and associatedcomponents are as described above and bear similar reference charactersto the cured spar member 518 and associated components, but with aleading ‘6’ rather than a leading ‘5’. The upper spar flanges 632, 636extend from the respective exterior surface 624 e of the forward and aftspar assemblies 643, 641. The lower spar flanges 634, 638 each form anacute angle relative to the respective exterior surface 624 e of thesupport beam 624 for the forward and aft spar assemblies 643, 641. Thelower spar flanges 634, 638 are each at angle from about 50 degrees toabout 85 degrees relative to the exterior surface 624 e of the supportbeam 624. In an embodiment, the lower spar flanges 634, 638 are each atan angle from about 60 degrees to about 84 degrees relative to theexterior surface 624 e. In another embodiment, the lower spar flange634, 638 are at angle from about 65 degrees to about 80 degrees relativeto the exterior surface 624 e. This embodiment is illustrative of a “C”spar with an outward configuration for the forward spar assembly 643 andthe aft spar assembly 641. The “C” spar with outward configuration canadvantageously provide the advantageous of the “Z” spar configurationbut even more so by using automated drilling and fastening duringinstallation of the skins and components to the top and bottom of thewing. In other embodiments, the torque box assembly 657 can include avariety of spar configurations and includes at least one “C” sparconfiguration in at least one of the forward spar assembly 643 and theaft spar assembly 641.

The step of locating a periphery 320 of the cured spar member caninclude identifying a part and accessing the corresponding tooling indexplans for the part, which can be performed by the numerically controlledmachining assembly 419. The tooling index plans can identify downstreamtooling features (for example, and not limitation, indexing holes andlocating planes) as well as the desired “as built” configurations, andinitial manufacturing work instructions. The tooling index plans canprovide downstream consumer information on how the designed part isintended to be manufactured and installed, which can significantlyreduce the cycle time and cost of tool design and final manufacturingwork instruction development.

Step 324 of the method 300 includes locating a plurality of secondarycoordination holes 433 in the cured spar member 418, which aresubsequently accurately drilled in step 326 to provide a plurality ofsecondary coordination holes 433 in the cured spar member 418. Theplurality of secondary coordination holes 433 can be located based onthe primary coordination holes 422, which can be performed by thenumerically controlled machining assembly 419. In an embodiment, thereare about 200 secondary coordination holes 433 in each cured spar member418. Then term “secondary coordination holes” in the cured spar member418 means holes that correspond to coordination locations in at leastone of the following: the lower composite skin assembly 151, the ribposts 146, a plurality of clevis fittings 142, the anchor assemblies147, and the engagement members 145. The primary and secondarycoordination holes 422, 433 establish the relationship of the componentsto each other and facilitate installation such that separate toolingfixtures are minimized. In one embodiment, the primary and the secondarycoordination holes 422, 433 are holes drilled to a nominal position at awidth of about 0.098 inch and having a +/−tolerance of 0.005 inches.Many parts and sub-assembled components include a plurality of openings442 that correspond to the secondary coordination holes 433 andfacilitate easy assembly of the cured spar member 418 and ultimatelyinstallation of the assembled parts to form a torque box assembly 157.

In step 328 of method 300, the cured spar member 418 undergoes assemblyto form a spar sub-assembly 420 on assembly bench 449 and uses onlystandard tooling such as hand-held drills. The step 328 includesassembly of the plurality of rib posts 146 to the spar member 418 at theplurality of the primary coordination holes 422 as shown in FIGS. 21Aand 21C. The clevis fittings 142 can be a plurality of clevis fittinghaving various configurations as shown in FIGS. 21A-21C. In oneembodiment, a clevis 437 includes bases 437 a, 437 c, and a supportfeature 437 b. The clevis base 437 a can be located with one hole andsecured to the cured spar member 418 with a fastener therethrough, thenthe support feature 437 b can be fixedly attached to the base 437 a. Thesecond base 437 c is located by the position of the support feature 437b and secured to the cured spar member 418 and the support feature 437b. The spar sub-assembly 420 can include fittings and components for theleading edge assembly 159 and cove edge assembly 161. The step 328 caninclude attaching a plurality of stiffeners 435 to the cured spar member418. The step 328 can advantageously provide a method for performingsub-assembly on a cured spar member 418 that does not require custom andexpensive tooling.

In an embodiment, the step 330 of the method 300 includes repeating theforming the spar sub-assembly step to form the aft spar assembly 141 andthe forward spar assembly 143. In an embodiment, shown in FIG. 22 , theforward spar assembly is constructed of two spar sub-assemblies 420designated as a right spar sub-assembly 141R, 143R and a left sparsub-assembly 141L, 143L.

An embodiment provides that the right and left aft spar assemblies 141R,141L and the right and left forward spar assemblies 143R, 143L are eachjoined with the engagement member 145 as shown in FIGS. 22A, 22B, and 23. The respective interior surfaces 141 i, 143 i of the aft and forwardspar assemblies 141, 143 are each fixedly attached to the first andsecond engagement surfaces 145 f, 145 d on the joining portion 145 j ofthe engagement member 145. In particular, in one exemplary embodiment,as shown in FIG. 23 , interior surface 143 i of the left forward spar143L is fixedly attached to the second engagement surface 145 d and theinterior surface 143 i of the right forward spar 143R is fixedlyattached to the first engagement surface 145 f. In an embodiment, anexterior plate 149 can be positioned over the butt joint of the left andright spar assemblies 420 to reinforcement the joint of the exteriorsurface 141 e, 143 e of the aft or forward spar sub-assembly 141, 143.In other embodiments, the engagement member 145 includes at least oneattachment surface on the interior surface 145 i of the joining portion145 i. The engagement member 145 can be constructed of at least one of acomposite material and a metallic material and can be constructed ofvarious materials, shapes and sizes to accommodate at least two sparsfor an aircraft and other structural members. In one embodiment, theengagement member 145 is a single machined part that splices the leftand right forward and aft spars to form aft and forward spar assemblies141, 143.

In an embodiment, each of the aft and forward spar assemblies 141, 143are generally straight and do not include a bend or kink as is found inthe prior art wing in FIGS. 1 and 2 . The generally straight aft andforward spar assemblies 141, 143 advantageously provides structuralstiffness and facilitates installation and accuracy of thereof by havingstraight surfaces for assembly. It should be appreciated that thetiltrotor wing structure can include at least one generally straightforward spar assembly 143 and aft spar assembly 141 constructed of avariety of materials, shapes, and sizes.

The method 300 includes providing assemblies for the installation steps.The lower composite skin 151 assembly is provided in step 332 andincludes a plurality of openings 442. The plurality of rib assemblies155 is provided in step 334 and includes a plurality of openings 442.The lower composite skin 151 and the plurality of rib assemblies 155 canbe transported for installation by hand and do not require cranes orother lifting equipment. In an embodiment, the lower composite skin 151is positioned in the fixture 449, which has a contoured surface thatprovides uniform structural support to the lower composite skin 151, islocated by tool holes to ensure proper alignment, and raised up to joinwith the bottom of the aft and forward spar assemblies 141, 143 suchthat the plurality of openings 442 align with the secondary coordinationholes 433 in the aft and forward spar assemblies 143, 141.

Step 336 includes installing the lower composite skin assembly 151 tothe aft and forward spar assemblies 141, 143. The installation step 336can include temporarily securing the lower composite skin assembly 151to the aft and forward spar assemblies 141, 143 with removable pins. Theaft and forward edges 151 b, 151 a are secured to the aft and forwardspar assemblies 141, 143, respectively, by at least one of adhesivebonding and fasteners. The adhesive bonding can include adhesives thatcure in ambient conditions or temperature sensitive. The fasteners canbe secured through secondary coordination holes 433 in the spar flanges425 of the aft and forward spar assemblies 141, 143 and in thecorresponding plurality of openings 442 in the lower composite skinassembly. In an embodiment, the plurality of openings 442 in the lowercomposite skin 151 can be drilled using the second coordination holes433 in the spar flanges 425.

The installation step 336 can further include providing a plurality ofanchor assemblies 147, positioning the anchor assemblies 147, andinstalling the anchor assemblies to the aft and forward spar assemblies141, 143. The plurality of anchor assemblies 147 attach the tiltrotorwing structure to a fuselage. In an embodiment, the plurality of anchorassemblies is located by a fixture tool and fastened to the aft andforward spar assemblies 141, 143 using fasteners.

The installation step 336 further includes installing a plurality of ribassemblies 155 to the aft and forward spar assemblies 141, 143 and tothe lower skin 151. The plurality of rib assemblies includes a pluralityof openings 442 in the joint members 250, 252 that are aligned with thesecondary coordination holes 433 in the rib posts 146 in the aft andforward spar assemblies 141, 143 and then temporarily secured thereinwith pins. In an embodiment, the skin flanges 240 do not include theplurality of openings 442 therein for securing to the lower or uppercomposite skin 151, 153 and are secured by paste bonding thereto.

In an embodiment, the rib assemblies 155, the lower skin 151, and theupper skin 153 are configured with fiberglass layers sufficient toeliminate the galvanic corrosion potential of the wing structure 109.

The installation step 336 can include installing a centerline ribassembly 156 with the rib post 145 p of the engagement member 145 byfixedly attaching the centerline rib assembly 156 to the rib post 145 pwith fasteners. In one embodiment, the centerline rib assembly 156 is arib assembly 155 as described herein.

The installation step 336 of the method 300 can further includeadjusting for tolerance buildup using tolerance adjustment members 146 tin the rib posts 146. A portion of the rib posts 146 can include atleast one tolerance adjustment member 146 t such as a slot for receivinga fastener that can be selectively adjusted in response to tolerancevariations during the installing step 336. In an embodiment, toleranceadjustment member 146 t is the width of two drilled holes. In oneembodiment, the tolerance adjustment members 146 t are provided on atleast one of the rib posts 146 on the aft spar assembly 141 and on theforward spar assembly 143. Once the tolerance adjustment members 146 thave been aligned and secured into position, the plurality of ribassemblies 155 is secured with at least one of adhesive and fasteners tothe respective rib posts 146.

The method 300 further includes step 338 of providing an upper compositeskin 153, and the step 340 of installing the upper composite skin 153onto the aft spar assembly 141, the plurality of rib assemblies 155, andthe forward spar assembly 143 to form a torque box assembly 157. In anembodiment, the upper composite skin is located using a fixture and isadhesively bonded to the aft spar assembly 141, the plurality of ribassemblies 155, and the forward spar assembly 143. In an embodiment, theinstalling step 340 can further include curing. In an embodiment, theadhesive can bond at ambient temperature or with a temperature sensitiveadhesive using a heating tool. In an embodiment, the curing step caninclude curing the entire torque box assembly.

In another embodiment, the curing can include curing a portion of thetorque box assembly 157. In one embodiment, a heating tool 460 isconfigured for curing a portion of the torque box assembly 157, as shownin FIGS. 24A-24H, by providing localized heating to a surface 480 whileavoiding thermal damage to surrounding components. The surface 480 canbe an exposed surface, adhesive between more than one surface. In otherembodiments, the heating tool 460 can be used to heat treat or expeditethe cure of surface resins, paints, fairing compound, and the like. Thelocalized heating provided by the tool 460 can provide at least one ofthe following benefits: reduced energy consumption; limits safetyconcerns related to a heated manufacturing area and surfaces therein;dimensional stability from thermal expansion; and additional tooling andprocesses may not be needed to compensate for thermal expansion of anentire component. In an embodiment, the adhesive is a room-temperaturecurable liquid, paste epoxy adhesives, or any adhesive or material thatis temperature sensitive such that heat speeds up the desired chemicalreaction or cure kinetics.

The surface 480 can be made of a material such as a composite ormetallic material having a temperature sensitive adhesive appliedthereto or a temperature sensitive resin therein. In an exampleimplementation, the surface 480 is in a fuel bay 484 of torque boxassembly 157 as shown in FIG. 24A. The surface 480 has a contour 480 athat can be curved, as shown in FIGS. 24A and 24B. The contour 480 a canbe a curved surface or a horizontal corner of the rib assembly 155 beingadhesively bonded to the upper composite skin 153, which can bedifficult to access and provide uniform heating thereto withconventional heating tools. In other embodiments, the surface 480 is avertical corner, straight, or other shapes and sizes of variouscomponents.

In a particular embodiment, the heating tool 460 is configured forheating a surface 480 of a fuel bay 484 in the torque box assembly 157to a temperature sufficient to effect a cure therein. The heating tool460 includes a heat source 462 having a discharge outlet 464 and amanifold 466. The heat source 462 can be a heating device that providesheated airflow such as, but not limited to, hot gas convention (e.g. aheat gun, hair dryer, or other hot gas supply), a furnace, a spaceheater, or other heat source. In some implementations, multiple heatsources of the same type or different types are used to heat the surface480. In an exemplary embodiment, the heat source 462 is a Masterflow®Heat Blower AH-501 made by Master Appliance Corporation. In anembodiment, the discharge outlet 464 is a round end of a barrel on aheat gun.

The manifold 466 includes an intake conduit 468 configured to releasablyconnect to the discharge outlet 464 and a chamber 470 coupled to theintake conduit 468. The chamber 470 includes a ventilation path 476 forproviding uniform airflow to heat the surface 480. The ventilation path476 includes a plurality of apertures 477 that can be round,rectangular, or other various shapes and sizes sufficient to provideuniform airflow to the surface 480. In one embodiment, the ventilationpath 476 is located along the upper edge 470 u of the chamber 470opposite to the bottom end 470L of the chamber 470. The bottom end 470Lis releasably engaged with the intake conduit 468 for receiving heatedairflow therefrom. In the exemplary embodiment shown in FIG. 24C theventilation path 476 is a plurality of various sized rectangular slotswith the end rectangular slots 478 longer than the middle rectangularslots 479. The ventilation path 476 can be configured to align generallywith the contour of the surface 480.

The chamber 470 is generally triangular in shape as shown in FIG. 24A.The chamber 470 includes a first wall 471 and a second wall 472 that canbe parallel to each other as shown in FIG. 24D to direct the flow of airtherebetween. The first and second walls 472 each includes a divergingportion 473 that is configured to provide uniform airflow through theventilation path 476. In this exemplary embodiment, the divergingportion 473 is a convex portion or shape that extends away from theventilation path 476. The convex portion 473 shown in FIGS. 24B, 24C,24D and 24E is disposed between the ventilation path 476 and the intakeconduit 468 and radiates from a base 473 b centered above the intakeconduit 468. The convex portion 473 radially protrudes symmetricallysuch that the center 473 c of the convex portion protrudes more than theouter edges 473 e and forms generally a cross-sectional “V” shape asshown in FIG. 24D. In the exemplary embodiment shown in FIG. 24D, thecenter 473 c of the curvature in the convex portion 473 creates an equaldistance (equal back pressure) for the airflow as the ventilation path476 radiates to the edges 473 e. The convex portion 473 internallychanges the direction and distance of the airflow such that the airflowin the center portion has the same distance of travel as the airflow atthe edges to provide uniform airflow through the ventilation path 476.The diverging portion 473 can mix or temper a portion of air through thechamber 470 to provide uniform airflow through the ventilation path 476.In an embodiment, the airflow through the ventilation path 476 is heatedconvection airflow for heating of a surface 480 that is adhesivebondlines.

Since the surface 480 can be a variety of shapes and sizes with variouscontours, the size and shape of at least one of the following of thechamber 470, the diverging portion 473, and the ventilation path 476 canbe adapted to provide at least one of mixing and tempering of airflow toprovide a uniform airflow from the ventilation path 476 to the surface480. In an illustrative embodiment, if the surface 480 is an oval shapedaccess panel having a rounded joint member 217 that required heating,the chamber 470 could have a generally rounded or oval shape. In otherillustrative embodiments, the chamber 470 could have a generallycruciform shape and can further include staggered and stepped features.In an embodiment, at least one of the following of the chamber 470, thediverging portion 473, and the ventilation path 476 are selectivelyconfigured to tailor the airflow through the ventilation path 476 to thesurface 480. In an embodiment, the chamber 470 and ventilation path 476conform to a contour of a surface 480. In another embodiment, thechamber 470 includes structural features such as vanes, nozzles, and thelike that assist in distributing and tempering the airflow therethroughto the ventilation path 476.

An embodiment provides that the chamber 470 includes a first portion 470a and a second portion 470 b that can be assembled and disassembled. Thefirst portion 470 a and the second portion 470 can be releasably engagedalong the centerline 470 c as shown in FIG. 24D. In an embodiment, thefirst portion 470 a and the second portion 470 b are snapped togethersuch that the edge 470 e of the second portion overlaps the edge 470 gof the first portion. The first and second portions 470 a, 470 b can besecured together using tape or snapped together using tab fasteners. Tofacilitate heating in space constrained areas such as the fuel bay 484,the first and second portions 470 a, 470 b can be assembled in the spaceconstrained area and then connected to the intake conduit 468. In anembodiment, the chamber 470 is configured for assembly and disassemblyfor space constrained locations such that the first and second portions470 a, 470 b and even more portions can be assembled and disassembledhaving various configurations, for example, a fan type configurationwith pieces that fold into themselves.

In an embodiment, the heating tool 460 can include an alignment member467 to minimize misalignment between the ventilation path and thesurface and support the weight of at least a portion of the heating tool460, as shown in FIG. 24F. The alignment member 467 is a stand member481 including a base 481 a connected to the chamber 470 and acylindrical feature 481 b. The base 481 can be removably attached to thechamber 470. The cylindrical feature 481 b is positioned in an aperture,for example, and not limitation, as 230 r in the rib web 230, to alignand support at least a portion of the heating tool 460. The stand member481 can be used to lock the chamber into position and for locating andaligning the ventilation path 476 with the surface 480.

In another embodiment, shown in FIG. 24G, the alignment member 467′ canbe a clip or clamp 482 a located on or near the upper edge 470 u of thechamber 470 and a clip or clamp 482 b located on or near the intakeconduit 468. The clips 482 a, 482 b are coordinated with structuralfeatures near or on the surface 480 to achieve and maintain properalignment and spacing. In an embodiment, the alignment member 467′includes at least one clip or clamp 482 a, 482 b at position to alignand secure the chamber 470 for proper alignment with the surface 480.The clip or clamp 482 a, 482 b can be in various locations on thechamber 470 and the intake conduit 468 as needed for a particularconfiguration of the heating tool 460.

In another exemplary embodiment, shown in FIG. 24H, the alignment member467″ can be a legs 4831 extending from a base 483 b to support thechamber 470 and a pair of feet 483 p located on or near the upper edge470 u of the chamber. The legs 4831 can be extendable or telescopinglegs. The pair of feet 483 p can maintain desired and uniform spacingbetween the ventilation path and the surface 480. The clip or clamp 482a, 482 b, the feet 483 p, the base 483 b, and the 4831 can be separateor integral to the heating tool 460.

The alignment member 467, 467′, 467″ can be used for locating,positioning, and locking the heating tool 460 into place for theduration of its operation and can be dissembled thereafter. In anotherembodiment, the alignment member 467 can include a plurality of pinswith locating features that line up with existing holes or offsetfeatures of the surface 480 to marry up to the surrounding surfaces.

In an embodiment shown in FIG. 24I, there is a method of curing acomponent for an aircraft 490 including the steps of applying atemperature sensitive adhesive to a surface 480 of a component in step492, the surface 480 having a contour; positioning the heating tool 460including a manifold 466 with a ventilation path 476 such that theventilation path 476 is adjacent to surface 480 by aligning theventilation path 476 to the contour 480 c of the component in step 494;and heating the exposed area of the component with uniform airflow fromthe ventilation 476 path in step 496. The chamber 470 and the intakeconduit 468 can be assembled prior to the positioning step 492; and, inan exemplary embodiment, the first and second portions 470 a, 470 b areassembled in the fuel bay 484 of the torque box assembly 157. Theventilation path 476 is aligned adjacent to the surface 480, which meansthe ventilation path is generally alongside, besides, or next to thesurface 480, to provide localized heating thereto. The heating step 496can involve heating the surface 480 from ambient temperature to about350 F; however, it will be appreciated that the contemplated embodimentscan involving heating higher than 350 F for certain surfaces. In anembodiment of the method of curing 490, the method can include applyingdirect heated air to the surface 480 of a curing area in a location thatis difficult to reach due to the structure of the component.Advantageously the method of curing 490 and heating tool 460 can provideheating by the ventilation path 476 within a heating zone HZ of thesurface 480 being heated without overshooting upper limits of curingtemperatures and avoiding thermal damage incurred upon the assembly orparts comprising the assembly. The heating zone HZ can be a periphery ofa component having adhesive or other curable material thereon ortherein. Moreover, the method of curing 490 and the heating tool 460 canprovide at least one of the following advantages: accelerated curekinetics of the surface 480 with the selected application of heatthereto; reduced cure time; improved cure properties; can increase andcontrol temperature ramp rates, particularly in insulative honeycombstructures, or structures with variable features such as thickness ormaterial thermal conductivities; minimizes the influence of variable andambient boundary conditions; enables a more efficient mode of heattransfer; and allows for localized heat to the surface 480 in adhesivelybonded components without overshooting upper limits of curingtemperatures.

Step 342 of the method 300 as shown in FIG. 26 includes installing aleading edge assembly 159 and a cove edge assembly 161 to the torque boxassembly 157 to form the wing structure 165 for a tiltrotor aircraft101. The step 342 can include installing fuel access covers 163 in thelower composite skin assembly 151.

Advantages of the method of manufacture 300 can include at least one ofthe following advantages: upstream spar assemblies 141, 143, skinassemblies 151, 153, and rib assemblies 155 reduce the need for assemblyduring the final installation steps in method 300, which reduces thenumber of fixtures needed during the installation steps by 60% ascompared to the prior art methods used in FIGS. 1 and 2 ; reduces thefloor space needed by about 50% as compared to the prior art methodsused in FIGS. 1 and 2 ; reduces the hours for assembly and installationof the torque box assembly 157 by about 32% when compared to themanufacture of the torque box of the prior art wing shown in FIGS. 1 and2 ; and the prefabricated lower composite skin 151 provides a flatbottom and requires only foam fillets in each corner of a fuel bay.

An embodiment provides a wing member 109 for a tiltrotor aircraft 101including a wing having a straight forward edge 109 a and a straight aftedge 109 b. Each of the straight forward edge 109 a and the straight aftedge 109 b are made of a left and right spar assembly 143R, 143L, 141R,141L, respectively. The wing 109 can include a lower composite skin 151and an upper composite skin 153. Each of the lower and upper compositeskins 151, 153 are a composite assembly including of a first skin 201, asecond skin 211, and a honeycomb core 207 disposed between the firstskin 201 and the second skin 211. The honeycomb core 207 is made from aplurality of honeycomb panels 203 positioned along the longitudinal axisof the first skin. The wing member 109 can advantageously provide atleast one of the following benefits: a straight wing with a simplifiedcross-section, which eliminates the need for costly splicing at contourbreak locations and reduces part count of the entire wing structure byabout 75% as compared to the conventional structure shown in FIGS. 1 and2 ; reduces the number of discrete tools; less fasteners as compared tothe prior art shown in FIGS. 1 and 2 , which means less deburring; thenumerous horizontal and vertical stiffeners needed for conventionalaerospace structures as shown in FIGS. 1 and 2 are no longer needed forbuckling resistance and to transfer the load and resist out of planebending forces; and the smooth lower composite skin interior surface canimprove fuel capacity.

At least one embodiment is disclosed and variations, combinations,and/or modifications of the embodiment(s) and/or features of theembodiment(s) made by a person having ordinary skill in the art iswithin the scope of the disclosure. Alternative embodiments that resultfrom combining, integrating, and/or omitting features of theembodiment(s) are also within the scope of the disclosure. Wherenumerical ranges or limitations are expressly stated, such expressranges or limitations should be understood to include iterative rangesor limitations of like magnitude falling within the expressly statedranges or limitations (e.g., from about 1 to about 10 includes 2, 3, 4,etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example,whenever a numerical range with a lower limit, R_(l), and an upper,R_(u), is disclosed, any number falling within the range is specificallydisclosed. In particular, the following numbers within the range arespecifically disclosed: R=R_(l)+k*(R_(u)−R_(l)), wherein k is a variableranging from 1 percent to 100 percent with a 1 percent increment, i.e.,k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . , 50percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 97percent, 98 percent, 99 percent, or 100 percent. Unless otherwisestated, the term “about” shall mean plus or minus 5 percent of thesubsequent value. Moreover, any numerical range defined by two R numbersas defined in the above is also specifically disclosed. Use of the term“optionally” with respect to any element of a claim means that theelement is required, or alternatively, the element is not required, bothalternatives being within the scope of the claim. Use of broader termssuch as comprises, includes, and having should be understood to providesupport for narrow terms such as consisting of, consisting essentiallyof, and comprised substantially of. Accordingly, the scope of protectionis not limited by the description set out above but is defined by theclaims that follow, the scope including all equivalents of the subjectmatter of the claims. Each and every claim is incorporated as furtherdisclosure into the specification and the claims are embodiment(s) ofthe present invention.

What is claimed is:
 1. A method of curing an aircraft component,comprising: applying a temperature sensitive adhesive to a surface of acomponent, the surface having a contour; positioning a heating toolincluding a manifold with a ventilation path such that the ventilationpath is adjacent to the surface by aligning the ventilation path to thecontour of the component; and heating the surface of the component withuniform airflow from the ventilation path; wherein the manifold includesa chamber with a diverging portion configured to provide uniform airflowthrough the ventilation path to provide heating to the surface.
 2. Themethod according to claim 1, wherein the heating step provides localizedheating to the surface.
 3. The method according to claim 1, wherein theheating step includes heating the surface from ambient temperature toabout 350 F.
 4. The method according to claim 1, wherein the positioningstep includes positioning the manifold such that the ventilation path islocated within a heating zone of the surface.
 5. The method according toclaim 4, wherein the heating zone of the surface comprises a peripheryof the component.
 6. The method according to claim 1, further comprisingassembling a first portion and a second portion of the chamber prior tothe positioning step.
 7. The method according to claim 1, furthercomprising assembling an intake conduit to a heat gun and assembling theintake conduit to the manifold.
 8. The method according to claim 1,wherein the positioning step includes positioning an alignment member toalign the ventilation path with the surface.
 9. The method according toclaim 1, wherein the positioning step includes supporting the manifoldwith an alignment member.
 10. The method according to claim 9, whereinthe alignment member is a stand member including a base connected to thechamber to support the weight of at least a portion of the heating tool.11. The method according to claim 10, wherein the base further comprisesa pair of legs extending from the base.
 12. The method according toclaim 9, wherein the alignment member comprises a clip and/or a clamp.13. The method according to claim 1, wherein the positioning stepincludes assembling a first portion and a second portion of the chamber.